Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: beaubicknese@yahoo.com on February 08, 2022, 05:41:08 PM

Title: Round top carburetor
Post by: beaubicknese@yahoo.com on February 08, 2022, 05:41:08 PM
Good morning, 

     I have gone though my carbs multiple times and just ordered new floats and needles for floats.  The bike starts well and rides well up to about half throttle then bike begins to stumble.  Also I have noticed the slides on round tops don’t drop down all the way allowing the idle screw to take over  and RPM to drop    I have to push down on number two slide to set it back to idle   Everything has been cleaned and set more then once.   I also am looking for a new carb throttle arm set up  if anyone has one   Number 4 has a broken fork on one side.  Makes no difference to previous issue however.   Carbs are synced and valves are done.   Running air pods but they are wrapped and socked for air restriction.  I have air screws almost completely turned it as well. 
Title: Re: Round top carburetor
Post by: philward on February 08, 2022, 06:08:13 PM
Tickover issues sounds like slides are set too high on the top adjusters - use Bryan's bench sync guide in Aladdin's Cave (sorry, can't access it to put the link on as on my phone) - I"m sure someone will be along with the link shortly

Sent from my moto g(50) using Tapatalk

Title: Re: Round top carburetor
Post by: beaubicknese@yahoo.com on February 08, 2022, 06:11:25 PM
Ya I have synched them 2 or 3 times   Set idle, adjusted each round top adjuster   As soon as any throttle is applied all 4 slides fail to return to closed even with return throttle cable.  I am at a loss on that one 
Title: Re: Round top carburetor
Post by: K2-K6 on February 08, 2022, 06:31:10 PM
The link here http://www.sohc.co.uk/index.php/topic,17769.0.html you'll need to follow it to the letter as the detail in it will give you a correct reset to best remove the problem you're experiencing now.

Don't you go missing any bits now  ;D
Title: Re: Round top carburetor
Post by: Bristolbadger on April 29, 2022, 01:55:17 PM
I had the same problem and fitting a new throttle return spring on the carbs sorted it beautifully, then I could adjust them and get the idle ticking sweetly.

It's nice when the cheapest and easiest first thing to try sorts it, maybe worth a go
Title: Re: Round top carburetor
Post by: Bristolbadger on April 29, 2022, 01:57:36 PM
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_221951/
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